1. Field of the Invention
The present invention relates to a method of manufacturing a thin-film transistor used in a display panel or the like for a liquid crystal display apparatus and, more particularly, to a method of manufacturing a thin-film transistor capable of stabilizing display characteristics in a display panel or the like.
2. Description of the Prior Art
For example, thin-film transistors are formed on a matrix type liquid crystal panel, and are used to control the ON/OFF operations of pixels that form the liquid crystal panel.
A conventional thin-film transistor has the following problem.
As described above, a thin-film transistor is used to control the ON/OFF operation of each pixel on a matrix type liquid crystal panel. A thin-film transistor with unstable characteristics may adversely affect the quality of a fabricated liquid crystal panel. Thus, to stabilize the characteristics of the thin-film transistor is significant in maintaining the quality of the liquid crystal panel.
The present invention has been made in view of the above situation of the prior art technique, and has as its object to provide a method of manufacturing a thin-film transistor the characteristics of which can be stabilized.
In order to achieve the above object, according to the main aspect of the present invention, there is provided a method of manufacturing a thin-film transistor wherein, when channel etching for removing predetermined portions of an ohmic layer and a diffusion layer thereof by plasma etching is to be performed, a surface of a semiconductor layer of a channel portion is formed to have predetermined steps.
In the above aspect, the predetermined steps have a height which is adjusted within 200 xc3x85 to 500 xc3x85 by plasma etching.
In the above aspect, plasma etching is performed by a plasma dry etching device.
In the above aspect, plasma etching is performed by introducing SF6/HCl/He=200/200/100 (SCCM) gas, CHF3/O2=180/180 (SCCM) gas, or SF6/HCl/He=50/50/100 (SCCM) gas into the plasma dry etching device.
As is apparent from the above aspects, in the thin-film transistor manufacturing method according to the present invention, when channel etching for removing a predetermined ohmic layer and a diffusion layer thereof by plasma etching is to be performed, a surface of a semiconductor layer of a channel portion is formed to have predetermined steps. Thus, the characteristics of the thin-film transistor can be stabilized. In particular, when the thin-film transistor according to the present invention is used in a liquid crystal panel, both a write current to a pixel electrode and an off-leak current can be stabilized, and good display characteristics can be obtained.
The predetermined steps in the thin-film transistor manufacturing method according to the present invention have a height which is adjusted within 200 xc3x85 to 500 xc3x85 by plasma etching. Thus, the characteristics of the thin-film transistor can be stabilized correctly.
Plasma etching in the thin-film transistor manufacturing method according to the present invention is performed by the plasma dry etching device. Thus, the surface of the semiconductor layer of the channel portion can correctly form the predetermined steps.
In the thin-film transistor manufacturing method according to the present invention, the plasma dry etching device performs plasma etching by introducing SF6/HCl/He=200/200/100 (SCCM) gas, CHF3/O2=180/180 (SCCM) gas, or SF6/HCl/He=50/50/100 (SCCM) gas into it. Thus, the surface of the semiconductor layer of the channel portion can form the predetermined steps more correctly.
The above and many other objects, features and advantages of the present invention will become manifest to those skilled in the art upon making reference to the following detailed description and accompanying drawings in which preferred embodiments incorporating the principle of the present invention are shown by way of illustrative examples.